When do you use a comma before or after but? It takes a little practice. But if you know the punctuation rules, it’s simple.
The comma rules to help you decide are easy to learn, use, and remember.
Let’s look at some examples of when you need to insert a comma or omit it.
Once you know the rules, you can make the correct decision every time. It all depends on the grammar and structure of your complete sentences.
Is there a comma before but?
Yes, you often add a comma. But you need to know two simple and easy to remember grammar rules.
After you do, it will be easy for you to decide.
All you need to do is look at your complete sentence to know when a comma is required.
Two simple but comma rules
There are two basic and simple rules to follow for comma usage.
1. You insert a comma when the two halves of your sentence can stand alone.
2. You omit the comma when the sentence halves can’t stand alone.
When do you use a comma before but?
To make sure you are correct, check if your sentence is joining two independent clauses.
In this case, both clauses will have a subject and a verb.
If each part of your sentence is independent, they can stand apart as whole sentences.
Then but, which is your coordinating conjunction, needs a comma to separate your two clauses.
Here are some examples to show you when it is required.
I wanted to go out for breakfast but my local café was closed. Incorrect
I wanted to go out for breakfast, but my local café was closed. Correct
This is because each part of the sentence can stand alone as individual complete sentences.
Each one has a subject and a verb, so you are connecting two independent clauses.
I wanted to go out for breakfast. Complete My local café was closed. Complete
More examples of correct usage:
He left home early, but he forgot to take an umbrella. Correct
My sister is leaving for Canada tomorrow, but she will return in three weeks. Correct
Susan doesn’t like sardines, but her sister loves all kinds of fish. Correct
We wanted to go to Spain for our holiday, but the hotels are too expensive in summer. Correct
I meant to buy some bread, but I forgot to stop off at the bakery. Correct
When do you omit the comma?
If the second part of a sentence is a dependent clause, there is no comma.
This happens when you cannot make a logical sentence from the second clause. It is dependent on the first clause for its meaning.
It is because there is no subject with a verb in the second clause.
Look at these examples.
The restaurant was fantastic, but very expensive. Incorrect
The restaurant was fantastic but very expensive. Correct
You can see that the second phrase is not a complete sentence.
The restaurant was fantastic. Complete Very expensive. Incomplete
Studying grammar is hard sometimes but interesting all the same. Correct
I went to the concert but left early with a headache. Correct
The rest of the sentence was easy to write but with poor spelling. Correct
Going to the gym is tough some mornings but good fun all the same. Correct
He played as well as he could but lost the match. Correct
The example sentences above show that there is no subject with a connecting verb in the second clauses.
Be careful, though, because there can be a verb. If the verb doesn’t have a subject, it is not an independent clause.
You can see this is the last example sentence above with the verb lost.
When do you use a comma after but?
If you start a sentence with but, you don’t need to use a comma.
You might want first to refresh your memory about starting a sentence with but.
You only add one when there is an adverbial clause or an extra word or phrase following it.
Think of it at the beginning of a sentence as marking an interruption to a sentence.
But, yes, indeed, there is plenty of space in the car for you.
But, on the other hand, I might go to Spain instead.
I was going to buy tickets for the new show, but, in fact, my husband had already bought them for me.
But, if you really want to know the truth, I can’t stand my boss.
College isn’t easy, but, well, you know how it is.
The good news about the comma
Does the comma go before or after but? Now you know the answer.
You have mastered the rule. I told you it was super easy.
I have more good news for you.
You can use the same three-part rule for a sentence with and, or, yet, and so.
1. Use a comma before the conjunction when the sentence halves can stand alone.
2. Don’t use a comma before the conjunction when the second clause can’t stand alone.
3. Use a comma after the conjunction when it is followed by an interruption.
Examples of the comma before and, so, yet and or
He went to London for two weeks, and he stayed at an expensive hotel.
Susan loves her cat, and she lets it sleep in her bed.
Mary loves her dog, yet she doesn’t let it onto her bed.
There was no chance of changing our flight, so we had to stay for two more days.
Tim missed his train, so he was two hours late for the meeting.
You can try for a free upgrade, or you can pay extra to be sure you get it.
My advice is don’t pack too much, or you will be charged for excess baggage.
Examples after and, so, yet and or
He went to London for two weeks, and, just like him, he stayed at an expensive hotel.
Susan loves her cat, and, naturally, she lets it sleep in her bed.
Mary loves her dog, yet, like many dog owners, she doesn’t let it onto her bed.
There was no chance of changing our flight, so, unfortunately, we had to stay for two more days.
Because you can use however as a synonym for but, it is worth noting this rule.
If you use, however, therefore, furthermore, or moreover at the beginning of a sentence, there is always a comma after the adverb.
However, she expects to finish her novel by summer.
Furthermore, we will buy twenty copies of your new book.
Therefore, we will be an active promoter of your new novel.
Moreover, we would like to write a review for our newspaper.
When you are joining two independent clauses, however, take care.
You can wrap however in two commas. But for the other conjunctive adverbs, it is often better to use a semicolon.
I plan to finish my book by summer, however, it could be a little later.
I received your suggested edits; therefore, I’ll take your advice and start on my second draft.
The edits were incomplete; moreover, it seems that the proofreading was poor.
You missed so many errors; therefore, I think I will need to find a new editor.
If you use these adverbs for emphasis, it is quite easy. Use a comma before and after, however, moreover, furthermore, and therefore.
You can, however, proceed with the corrections.
It was, moreover, a very poor effort.
It is, furthermore, out of my control.
You may, therefore, continue with the project.
It is easy to learn the punctuation rules for coordinating conjunctions.
You can also use a reliable grammar checker to help you check online for your correct usage.
Just take a few minutes to make sure you understand the basic rules and then lock them away in your memory.
If there is a subject with a verb in the second clause, use a comma. If there is no subject with a connecting verb, omit it.
Here is a screenshot of some of my article text in Prowritingaid. You can see that the mistake is clearly marked with an explanation of the punctuation problem.
You can always do a similar easy check if you are a Grammarly user.
And yes, I did a full check, and I got all green lights for my punctuation.
Yes, there are some complicated rules that can cause confusion. The ones for cumulative and coordinate adjectives or a comma splice can be a bit tricky.
It is true that punctuation can be complex and often open to interpretation. It is especially so for the Oxford Comma.
Luckily, the rules in this article are easy. So you can leave all the other comma rules for another day.
I’m always reminded of this quote when I think about punctuation.
“I spent all morning putting in a comma and all afternoon taking it out.” – Oscar Wilde.